A multiple tuned multiple fed broadband MF antenna

A multiple tuned multiple fed (MTMF) type antenna can be considered as comprising two or more elements electrically connected at their top ends, or as an antenna system comprising separate elements, individually fed and closely spaced, so that in effect they are radiation coupled; the azimuthal radiation pattern is omnidirectional. The author has studied both types of multiple tuned antenna systems by numerical and by experimental modeling. This paper is a result of the author revisiting, by computer simulation, a MTMF antenna system comprising four inverted-L type elements. The early studies for electrically small antenna systems showed that such antenna systems could have bandwidths that far exceed that for any VLF/LF antenna system of comparable size. The present paper has brought to light, the fact that a very wide BW can be realized for a resonant MTMF antenna system, bandwidth f_max/f_min > 2:1 for SWR < 2:1. The paper describes a medium frequency antenna, but the system can, of course, be used at any frequency, providing that the dimensions are scaled in accord with frequency. For the medium frequency case, the useable frequency range is > 3:1 and bandwidth is an important consideration.